Collapsible backrest



FIG. 1 is a left, rear, top perspective view of a collapsible backrest showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left elevational view thereof, the right elevational view being a mirror image of the left elevational view;

FIG. 5 is a top plan view thereof;

FIG. 6 is a left elevational view of the collapsible backrest folded to provide a collapsed position; and,

FIG. 7 is a left, front, top perspective view thereof.

The broken lines shown in the drawings are for illustrative purposes only and form no part of the claimed design. 

We claim the ornamental design for a collapsible backrest, as shown and described. 